A new model of the cross-axis synchronous flow-through coil planet centrifuge was designed and fabricated at the NIH machine shop. The apparatus holds a pair of multilayer coil separation columns one on each side of the rotary frame at an off-center position. 3.8cm from the centrifuge axis and 13.5cm from the midpoint of the rotary shaft. The capability of the apparatus was evaluated in terms of retention of the stationary phase and partition efficiency using aqueous-aqueous polymer phase systems composed of dextran T500 and polyethylene glycol 8000 where the pH of the solvent was adjusted by 10mM potassium phosphate. The results indicated that the present system can hold a stationary phase at 45% of the total column capacity at 900 rpm and at a flow rate of 1ml/min. The performance of the apparatus was demonstrated in separation of various stable proteins including human serum albumin, alpha and gamma globulins, and histones.